Electric fuse device



March 27, 1934.

J. A. TEN BROOK ELECTRIC FUSE DEVICE Filed July 26, 1952 Patented Mar. 27, 1934 UNITED STATES .LECTRQ FUSE DEV Sohn A, Ten Brook, Mount Airy,

App Juiy 26 i532, Serial No. 624152352 8 laims.

The subject of my invention is an electric ruse device. One element of the device the fuse proper or a member adapted to volatilize, explode or otherwise generate pressure upon the passage of an excessive current 'therethrougl'r Another eleinent is a switch or ci adapted to be separated by the excess generated.

A third elernent consists of a liquid, Viscous, resilient, exible or solid dielectric material ar ranged to be interposed between the two contacts or" the switch when the latter are separated extinguish the arc or to prevent the reestablishment thereof.

For a further exposition oi my invention reierence may loe had to the annexed drawing specication at the end whereof rny invention will be specifically pointed out and claimed.

In the drawing,

Figure 1 is a side elevation of my device with parts broken away in vertical cross section showing the switch in closed position.

Figure 2 is a side elevation of a modification iny device with parts broken away vertical contacts pressure cross section showing the switch in open position.

Figure 3 is a View similar to Figure 2 oi another modification.

The embodiment of my device chosen for illustration in the drawing is a type of fuse device for use to protect transformers of electric distributing systems. In this embodiment the device comprises a hollow terminal 1 having a cap or other closure 2 therefor. This cap or closure is adapted to receive the fuse proper which cor sists of two spaced electrical contacts fi and 5,

one of which is in contact with the cap 2 and the other oi which is in contact with the terminal 6 ci the switch hereinafter mentioned. Contacts 4 and 5 are separated by insulation 3 which in the modification shown encloses two grains of gun powder (not shown). Contacts Il and 5 are connected by a fusible strip 33.

Terminal l also surrounds an insulating bushing '7 which has a shoulder 8 at the lower end thereof cooperating with the shoulder El on contact 6 to support the contact. Bushing '7 is supported by the screw threads 16 on the lower internal side of terminal l or by the tube 16 which is connected to the screw threads.

The switch consists of contact 6 which, as shown in Figure 1, has a hollow, tapered interior. Fitting into this tapered interior is a cooperating contact 11.

Within contact 6 is mounted a dielectric, generally indicated at 12, which may be either liquid,

l. 20de-.i290

viscous, flexible, resilient, or solid. As shown in is inodication it consists or" a glass tube 13 rounding a non-conducting liquid lll, such as carbon tetrachloride. Dielectric l2 is ported on a washer l5 or" insulating material. The threads lo on the lower end of terminal l cooper te with threads on the upper end of insulating tube 16 which serves to space terminal l from the lower terminal 17. Tube i6 may conveniently be made or" a material which possesses mechanical strength and high insulating quali- Tube 16 is shown as being circular in cross section but may be square, rectangular or of any other convenient shape. Contact 11 is elec- Lrically conneced to terminal 17 by cable i8 which is firmly attached to terminal 17 as by screw i9. Terminal 17 carries at its lower end cap 2G having a perforation 2l therein through which cable 18 passes loosely.

The operation of iny device is as iollowsz-n normal operation the ruse is connected into the line by rneans oi clips (not shown) which engage the outer surfaces of terminals l and 1'? so as to hold the fuse device in the upright position shown in the drawing. Upon the passage of a current oi"- the ina n'tude against which the fuse device is designed protect the circuit to which it is connected, the fuse (elements 3, 4 and 5) blows, volatilizes, explodes or otherwise generates pres-- sure. This pressure is transmitted through the interior of contact 6 to washer i5 and contact ll. Due to the tapered rit between contacts 6 and il, the latter is expelled from contact 6. The force of the pressure generated breaks glass 13 and holds liquid 14 and washer l5 against the end of contact 1i. This causes the arc which is drawn between contacts 6 and l1 to be oi a hollow uhular shape since the arc must jump around the edge of the dielectric washer 1'* and the dielectric le in contact therewith. rihe force oi the explosion and the movement oi contact ll in tube 16 is slightly cushioned by the air in tube 16 and terminal 17, the air being slightly compressed due to the restricted area of hole 2l through which it must escape. Contact l1 is also cushioned by the tendency of cable i8 to coil upon itself to form a resilient mass as is best seen in Figure 2. Contact 11, cable 18 and oriiice 2l are so proportioned that contact 1l is brought t0 rest slightly below the end of tube 16 so that dielectric washer l5 is still within the end of the tube 16, as is best seen in Figure 2. The dielectric 14 surrounds washer l5 and fills up any interstices between washer 15 and tube 16 so that the dielectric is interposed into the arc drawn between the contacts 6 and 11 and completely smothers the arc and prevents its reestablishment. The fuse device may be restored to its original condition by dismantling the parts and inserting a new fuse and fresh dielectric and reengaging contacts 6 and 11 in the position in which they are shown in Figure 1. Contacts 6 and 1l may conveniently be compressed together so that it requires a pressure of S00 lbs. to separate them.

The modincation of my device shown in Figure 2 is the same as that shown in Figure 1 except that a viscous dielectric 114 is employed instead of the liquid dielectric 14 shown in Figure l. ri'he viscous dielectric 114 may conveniently be petroleum jelly or any other grease having a high dielectric or insulating property. The dielectric 14 may be simply packed within contact 6 and supported upon washer l5 or supported directly upon contact 11 with washer 15 omitted.

The modification shown in Figure 3 is similar to that shown in Figures l and 2 except that a solid dielectric 115 is employed. This dielectric consists in lengthening the washer 15 of Figure i to a considerable length so that when the fuse device has operated, the dielectric 115 extends to a considerable distance into tube 16 and thereby interposes, an allnost solld dielectric barrier consisting of tube 1G and washer 115 between the contacts 6 and 11. When a dielectric of the type disclosed at 115 in Figure 3 is employed, the dielectric 115 may conveniently be made of a resilient or flexible insulating material so that the dielectric mushrooms or spreads over the end of tube 16 thereby forming a solid dielectric barrier between the contacts 6 and 11.

I do not intend to be limited in the practice of my invention save as the scope oi the prior art and of the attached claims may require.

I claim:

l. An electric fuse device including in combination, a iuse adapted to generate pressure upon the passage of an excessive electric current therethrough, a pair of contacts arranged to separate under said pressure, a solid dielectric arranged adjacent said contacts, and a iiuid dielectric other than said fuse arranged within one oi said contacts, said solid dielectric and said iluid dielectric being arranged to move into position between said contacts when they are separated to extinguish the arc therebetween.

2. An electric fuse device including in combination, a casing, a iuse in said casing adapted to generate pressure upon the passage of an electric current therethrough, a pair of contacts in said casing arranged to be eparated by said pressure, means for cushioning and stopping the movement or" one of said contacts within said casing, and a dielectric arranged to be interposed between said contacts when they are separated.

S. ein electric fuse device including in cornbination, a casing, a fuse in said casing adapted to generate pressure upon the passage or an excessive electric current therethrough, a pair of contacts arranged so as to be separated by said pressure, a cable connected to one of said contacts for conducting current thereto when said contacts are closed, means including said cable for cushioning` said contact within said casing to stop it after movement, and a dielectric arranged to be interposed between said contacts when they are separated.

4. An electric fuse device including in combination, a fuse adapted to generate pressure upon the passage of an excessive electric current therethrough, a hollow contact arranged adjacent said fuse to receive said pressure, a movable contact having a tapering fit with said hollow contact and adapted to be separated therefrom by said pressure, and a dielectric in addition to said fuse arranged within said hollow contact when the contacts are closed and arranged to be interposed between said contacts when they are separated.

5. An electric fuse device including in coinbination, a fuse adapted to generate pressure upon the passage of an excessive electric current through it, a pair of contacts arranged so as to be separated by said pressure, a solid dielectric arranged adjacent said contacts, and a viscous dielectric in addition to said fuse arranged adjacent said contacts, said solid dielectric and said Viscous dielectric being arranged so as to be interposed between said contacts when they are separated.

G. An electric fuse device including in coinbination, a fuse adapted to generate pressure upon the passage oit an excessive electric current therethrough, a pair of contacts arranged to be separated by said pressure, a tube ci" insulating material within which one of said contacts is moved by said pressure, and a dielectric arranged so as to cooperate with said tube to forni a complete dielectric barrier between said contacts when they have separated.

'l'. An electric fuse device including in combination, a pair of terminals, an insulating tube cooperating with said terminals to form a casing, a fuse in said casing, a means tor said fuse adapted to melt upon the passage of an excessive electric current therethrough. and to generate pressure, a pair of contacts mounted within said casing adjacent one end of said tube and adjacent said fuse, said contacts being adapted to separate under said pressure, means adjacent the opposite end of said tube for cushioning and stopping one of said contacts upon its movement, a solid dielectric mounted adjacent said contact a second dielectric mounted adjacent sai tacts, said solid dielectric and said second dielectric being arranged to coopera-te with said tube to form a complete dielectric barrier between said contacts when they have separated.

S. An electric fuse device includin, in combination, a fuse adapted to generate pressure upon the passage of an excessive current therethrough, a stationary contact adjacent said fuse, a movable contact adapted to be separated -from said stationary contact by said pressure, and a dielectric other than said fuse interposed between said use and said movable contact.

JOHN A. TEN BROOK. 

